News · 8 October 2026

The SD-JWT differential-fuzzing paper is out in Springer LNCS

“Spec-as-(N+1)-Oracle Differential Fuzzing of SD-JWT Presentation Verification” is published in Springer's Lecture Notes in Computer Science as a chapter of the STM 2026 proceedings, pages 103–119, doi:10.1007/978-3-032-41330-7_6. The paper was presented on 17 September 2026 at the 22nd International Workshop on Security and Trust Management, co-located with ESORICS 2026 at Sapienza University in Rome.

The method treats the specification itself as one more oracle beside the N implementations under test. Selective-disclosure JSON Web Tokens (SD-JWT) let a holder reveal some claims and withhold others; a verifier that returns success while quietly discarding a disclosed claim produces no error anyone can observe. The talk opened on a single byte in a disclosed family name: the issuer's signature and the key-binding token still verified, yet one widely used library silently replaced the byte, returned success and lost the name, while the reference oracle rejected.

The campaign ran 43,512 mutated presentations and recorded 21,356 disagreements between verifiers. Those are not 21,356 vulnerabilities: they reduce to a small number of classes, each version-bound, and the paper says so. Findings were disclosed to the maintainers before publication; where an embargo still applies, the affected library is not named here.

The public artefact that accompanies the paper is on Zenodo, 10.5281/zenodo.21744555. A companion conformance census of SD-JWT verifiers, and the verifier instrument in the Lab, continue the line.

The paper on the Research page → · Rome, in the field report →